Air filter



Feb. 18, 1941.

c. F. HAssELWANDER AIR FILTER Filed June 2o, 1938 FIG 4 5 Sheets-Sheet 1 INVENTOR L 1l/DE E /7//15554 MAM/JE@ t TORNEY Feb. 18, 1941. F, HASSELWANDER 2,232,065

AIR FILTER Filed June 20, 1958 3 Sheets-Sheet 2 /NI/ENTOA i CLAUDE Hasse/.w/r/vnc-R BY A TORNEY FIGQ |167 FIGS Feb- 13 1941-- c. F. HAssvELw/.LmDL-tRl 2.232.065

AIR FILTER Filed June 20, 1938 3 Sheets-Sheet 5 F'IGIZ /N VENTO/e E F. /v/AasEL M14/v0.15@

CLA un A TT RNEY Patented Feb. 18, 1941Y AIR FILTER claude F. nasseiwander, Rochester, N. y., assignor to Staynew FilterCorporation, Rochester, N. Y., a corporation of New York Application June 20, 1938, No. 214,678 I 2 Claims.

This invention relates to airfilters and las for its principal object togreatly reduce the fire hazard in filters embodying aninilammable filtering medium.

Another object of this invention is to so construct an air iilter that its inflammable filteringmedium will-` not readily catch iire. A further object of this invention is to construct an air lter embodying inflammableltering medium so that when set are its combustion will be retarded and restricted to small areas.

All these and other objects and attendant advantages will become more readily apparent from the detailed description of the invention which follows, reference being had to the accompanying drawings in which- Figure 1 is a front elevation ofv a filter panel embodying the novel illterconstruction.

Figure 2 is anenlarged detail sectional view taken on the line 2st-4a: of Figure 1.

Figure 3 is an enlarged detail sectional view taken on the line 3ra-3a: of Figure 1.

Figure 4 is an enlarged detail sectional view taken on the line zr-4:1: of Figure l.

Figure 5 is a section taken on the line 5:1.'-531 of Figure 4.

Figure 6 is a plan View of a portion of the iiltering medium and its mounting. e

Figure 7 is a cross section thereof taken on the line lx-1.2: of Figure 6.

Figure 8-.is a cross section of a modified form ofthe filtering medium and its mounting.

Figure 9 is a plan view of a portion of the filtering medium.

. Figure 10 is a top plan view and partial horizontal section'of a modified form of the lter panel embodying my invention.

Figure 11 is a vertical sectional view thereof taken on the line Ilm-l In: of Figure 10. 4 Figure 12 is an enlarged vertical sectional view of the upper portion of the filtering medium provided with a modified end sealing member.

The filter, forming the subject matter of this invention, is especially adapted for use in filtering units having replaceable or renewable lter inserts. In the construction of thevlter preferably cotton or Wool felt is used for the filtering medium but other material or fabrics having suitable ltering properties may be used instead.

,As illustrated in Figures 6 and' 7 of the drawings, -a suitable layer of the filtering medium .l is placed between the metal screens 2 and 3 which have a mesh that is preferably one quarter inch or less. The screens are located so that the edges of the filtering medium project beyond them and provide ailexiblesealing flange A 4 around the entire perimeterof'the filter as will hereinafter appear. .The screens and filtering sheet are fastened together along the edges and at suitable points by stitchingv or otherwise fastening the screens together -with the filtering sheet between then1. Suitable'thread, wire o r staples may be used for this purpose in order to rmly clamp the screens together along predetermined lines, as for example at '5` and 6 in Figures Gand'l so' that the screens with the filtering medium are divided into small individual `filtering areas around which the thread, Wire or staples `form a fige restricting barrier by compressing the fil- I tering medium between the screens along the line of connection.

In Figure 9 I have illustrated a form of filtering medium ,which is prepared to incorporate therein re restricting barriers. This is done by coating the surface or impregnating the iilte'r-- 'ing medium at suitable intervals along narrow strips 8, 8 with a fire resisting medium such as= water glass in such a manner that these strips divide the area of the filtering medium into a series of sections surrounded by the fire resistingV water glass. In this way the combustion of the liilteri'ng'material in each section is arrested by the fire barrier provided by the strips of re resisting coating which surrounds them.

Mounting the flltering medium between metal screen's confines the filtering mediumbetween efiicient heat conductors which carry oif and quickly distribute the heat that may be applied to the lter in case of re. This action, in addition to the well known fact that a name will not pass thru a screen, will protect the ltering medium from being. quickly set are when a flame directly impinges against the filter. The only thing thatl can happen when fire is brought incontact with the filter is thatthe filtering medium will char with a slow combustion and even this will be restricted to small areas by being arrested at the fire barriers-provided in the filter as above described.

With the filtering medium held in place be- 45 'and il which are telescoped together `to hold the o f the cover.

` filter.

adapted to embrace the i y andfa 1ocking-ilange2l projecting from the secin a frame or panel made up of two sections Ill lter between them.

Section Il of this ilter panel has the sides l2 and ends Il including a flange il which project inwardly therefrom. The folded filter is placed into this panelso as to have the ends of one side of the V shaped folds rest against the ange Il -while the sealing flange 4, provided bythe protruding ltering medium, adjusts itself and is yieldinglyheld against the sides and ends of the panel section by` the `screens to prevent air from passing thru the panel past the edges of the After the mier is paced into panel section lo a similarpanel section Il is telescoped over it to have its sides l5 and ends I6 embrace the corresponding'sides and ends of section I0 while its inwardly extending flange II- rests against the opposite ends of. the v shaped folds of the filter.

In order to keep the V shaped folds of the filterproperly spaced, the flange I'I is provided on its under side with a series of spacing fingers .il along each side of the panel section. These spacing fingers are adapted to part way engage l into the v shaped folds to uniformly hold them expanded and spaced in the lter panel.

For the purpose of locking panel section Il to section` I il, a pair of locking members i9, I9 are.

provide a laterally extending nan'ow lockingchannel between them. This locking channel is flange Il of section il tion' I0 so as to -hold these two anges and in turn the two sections locked together.

In the modiiied form of the filtering panel illustrated in Figures 11 and 12, the casing 2i, as

well as the removable cover 26 thereof, are prol vided with spacing ngers I8. On the casing 25 these spacing fingers are carried bytwo cross members 21, 21 which extend across the open `end of the casing` and on the cover 26 the spacing .fingers are carried'by a central cross member 2C and by suitable anges 29 at the top and bottom In this way the foldsof the lter- Y 2,232,065 .of the folds. The' computed mier is mounted ing medium are held expanded at the front and back thereof.

A pair of spring latches 30, 30, can-led bythe casing and passing thru suitable openings Il in the cover, are used to removably lock the cover 5 26 tothe casing 25. f

Instead of having the ltering medium project beyond the edges of the screens on each side thereof so as to provide a sealing strip along the top and bottom of the folds, aseparate felt strip l 32 may be folded over the top edge of the iilter from one screen to the other, as illustrated in Figure 12, and suitably fastened in place to the screens. J

f To hold the edges of the ends ofthe filtering l `medium in place on the inside wall of the casing of the ltering panel, the anchoring ange Il is provided on the inside of the filtering panel.

'I'his iiange angularly projects from the inside wall to permit the edge of the filtering medium to engage between it and the wall of the casing as illustrated in Figure 10.

From the foregoing it will be apparent that my novel construction of a filter panel and novell iilter results in an .extremely simple, inexpeni sively constructedbut highly elcient lter conf struction. Some changes may be made in the construction and arrangement of parts without departing from the real spirit and purpose of the invention 4and it is my intention to cover by my 30l claims any modified forms of the structure which `may be reasonably included within their scope.

I claim:

1. A filtering medium for a nre resisting airfilter comprisingv a sheet of woven or compressed fibers yand means dividing the surface of said sheet into restricted areas, said means comprising a non-inflammable coating so as to surround said restricted areas with a'iire resisting barrier.

`2. A iiltering medium for a fire resisting air filter comprising a sheet of woven or compressed fibers and nieans dividing the sheet into restricted sections, said means comprising a non-iniiammable substance applied to thefiltering medium in strips for impregnation of the filtering. medium around the restrictedsections so as to surround said sections with a fire resisting barrier.

CLAUDE F. HAssnLwANpEa. 

